Largest alternator for 8.3 that's a direct swap?

[TechnoWeenie]

Seems like there are 2 prevalent models. A 75A and 140A. Anything higher than that?

 

[wheelspinner]

Seems like there are 2 prevalent models. A 75A and 140A. Anything higher than that?

Even if you go bigger-the installed wiring won’t like it

 

[TechnoWeenie]

Even if you go bigger-the installed wiring won’t like it

I'll be upgrading wiring to feed a 20kwh+ battery bank in the rear.

 

[simp5782]

160amp part # 61000853

Any alternator shop can rebuild it with more winding to increase the amps

Seems like there are 2 prevalent models. A 75A and 140A. Anything higher than that?

 

[Weldman]

So you are trying to charge a 24VDC battery bank @ 20kWh which equals around to 833Ah if I am not mistaken at a C rate of .1 a 140A would be sufficient even with all the lights on the rig on. That means you are running around with at least 8 GC's or (12) 2V batteries which means powering up a camper of sorts. Switch to LED headlights on your rig and such and you will have plenty power left over from 140A alternator.

 

[TechnoWeenie]

So you are trying to charge a 24VDC battery bank @ 20kWh which equals around to 833Ah if I am not mistaken at a C rate of .1 a 140A would be sufficient even with all the lights on the rig on. That means you are running around with at least 8 GC's or (12) 2V batteries which means powering up a camper of sorts. Switch to LED headlights on your rig and such and you will have plenty power left over from 140A alternator.

I know the math.

These batteries can accept more than 100A EA, and there will be at least 4 of them. I just want them to recharge as quickly as possible in the event that there's clouds for a week and my 1200W+ planned solar array is only putting out 100W and isn't keeping up with the loads. Idling the truck for 2-3 hours a week in the event of no sun to recharge batteries if I'm boondocking is better than running it for 8 hours to recharge the same amount.

The alternative is a small 24V generator, which doesn't make much sense. That's one more thing to carry around, one more thing to maintain, and if I get gas one, another fuel to carry around. A 24V diesel gen would be $$$ and use about the same amount of fuel (and in some cases, more) than the truck would. Since the 8.3 even at high idle to avoid wet stacking shouldn't be more than .75-1GPH (I'm sure Wes can jump in on this if I've been reading wrong).

Also.
https://www.steelsoldiers.com/threads/the-weeniewagun-v3.205898/#post-2512842

 

[87cr250r]

The wet stacking bit is backwards. Operating engines at high idle causes wet stacking. Constant speed engines operating at light loads are very prone.

 

[Weldman]

Only going to have 1200W of solar for a 20kWh battery and you are worried about an alternator having enough power to quickly charge a lead acid battery more than .1 C rate. Never mind I’m moving on, I’ll find the door, though I will leave this here…

 

[TechnoWeenie]

Only going to have 1200W of solar for a 20kWh battery and you are worried about an alternator having enough power to quickly charge a lead acid battery more than .1 C rate. Never mind I’m moving on, I’ll find the door, though I will leave this here…

Why do you keep assuming I'm running SLA?

Yes, 1200W is generally enough to more than keep up with usage. The larger battery bank is to offset days with poor solar.

A 1200W solar array on an average day (5 hours, more in summer, less in winter, and that's only peak solar) would generate 6,000w/h minus line loss, charging inefficiency, etc. Current estimated loads are about 1kw/day.

You don't fully understand the design specifications, yet you continue to make assumptions. All I asked for was suggestions on a more powerful alternator.

 

[162tcat]

Have you considered a pto generator? Can go plenty big and load the engine while using a regular alternator for driving.


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[Steelreaper80]

How many amps in an alternator is actually required? I swapped to a 21SI clone that is 70 amp and it seems to be doing just fine after 3 years. Always keeps the batteries up and runs all the lights on the truck and M322 trailer with no issue. I have installed a 2000W 24V pure sine inverter and it runs that as well. I have a little 1500w single burner cook stove in my truck that I use to occasionally heat up a can of stew or soup. When it is on it does pull down the voltage gauge to the bottom of the yellow even with the truck at idle but as the truck runs it keeps the batteries charged back up in a short time. I was just wondering if it was worth the money to upgrade to a 140 amp or just run what is already installed.

 

[TechnoWeenie]

How many amps in an alternator is actually required? I swapped to a 21SI clone that is 70 amp and it seems to be doing just fine after 3 years. Always keeps the batteries up and runs all the lights on the truck and M322 trailer with no issue. I have installed a 2000W 24V pure sine inverter and it runs that as well. I have a little 1500w single burner cook stove in my truck that I use to occasionally heat up a can of stew or soup. When it is on it does pull down the voltage gauge to the bottom of the yellow even with the truck at idle but as the truck runs it keeps the batteries charged back up in a short time. I was just wondering if it was worth the money to upgrade to a 140 amp or just run what is already installed.

The thing about 24V is it's half amperage compared to 12V. So a 70A 24V alternator is akin to a 140A 12V alternator. Watts are watts.

With these trucks, the only real electronic draw is your lights, ABS, and the fuel shutoff solenoid (and the starter).

The solenoid can be bypassed, so these trucks CAN run with NO alternator, and NO batteries, as long as they have juice to start the truck.

Realistically, with ALL lights on, and fuel shutoff in place, maybe, 20A, tops?

If you have LED lights, a fraction of that.

The idea behind wanting BEEFCAKE alternator is to use it to charge a massive battery bank as a backup. Like 20KW+, for comparison, that 24V 70A alternator is 1680 Watts, so it'd take an entire day to charge a battery bank that's depleted. A 200A or 400A would be 4800/9600W respectively, meaning about 6/3 hours to charge from dead.

 

[Steelreaper80]

The thing about 24V is it's half amperage compared to 12V. So a 70A 24V alternator is akin to a 140A 12V alternator. Watts are watts.

With these trucks, the only real electronic draw is your lights, ABS, and the fuel shutoff solenoid (and the starter).

The solenoid can be bypassed, so these trucks CAN run with NO alternator, and NO batteries, as long as they have juice to start the truck.

Realistically, with ALL lights on, and fuel shutoff in place, maybe, 20A, tops?

If you have LED lights, a fraction of that.

The idea behind wanting BEEFCAKE alternator is to use it to charge a massive battery bank as a backup. Like 20KW+, for comparison, that 24V 70A alternator is 1680 Watts, so it'd take an entire day to charge a battery bank that's depleted. A 200A or 400A would be 4800/9600W respectively, meaning about 6/3 hours to charge from dead.

I upgraded the headlights to LED, the trailer lights are all LED minus the tail lights, the truck tail lights are stock, and my gauge lights are all LED. I removed the fuel shut-off solenoid. I run 2 group 31 batteries and they seem to stay topped up all the time even after sitting for over a month. I ran a 110v USB adapter from the inverter that my phone/Garmin plugs into. I probably draw very little power even with everything on. I was just wondering if I should upgrade but I don't think I really need to. I run some power tools from the inverter occasionally or my 1 burner stove. The stove is only run enough to heat a can of soup then shut off. A few minutes of idle and it seems to be charged back up.

 

[TechnoWeenie]

I upgraded the headlights to LED, the trailer lights are all LED minus the tail lights, the truck tail lights are stock, and my gauge lights are all LED. I removed the fuel shut-off solenoid. I run 2 group 31 batteries and they seem to stay topped up all the time even after sitting for over a month. I ran a 110v USB adapter from the inverter that my phone/Garmin plugs into. I probably draw very little power even with everything on. I was just wondering if I should upgrade but I don't think I really need to. I run some power tools from the inverter occasionally or my 1 burner stove. The stove is only run enough to heat a can of soup then shut off. A few minutes of idle and it seems to be charged back up.

The stock alternator is overkill to just run the truck. No one needs to upgrade unless they have a specific use case.